Adventitial root extract of oplopanax elatus alleviates rheumatoid arthritis via inhibiting NETosis
摘要
The adventitial root extract of Oplopanax elatus (OE) is a Chinese herbal extract that exhibits anti-inflammatory and antioxidative properties. We hypothesized that OE might have a protective effect on rheumatoid arthritis, and further investigated its mechanism of action.
MethodsThe levels of cell-free DNA (cfDNA) in plasma and synovial fluid of rheumatoid arthritis (RA) patients were detected by PicoGreen assay, and the correlations between cfDNA and RA clinical features were analyzed. The cytotoxicity of OE to RA neutrophils was assessed by CCK8 assay, and the production of reactive oxygen species (ROS) was measured by using the DCFH-DA probe. The effect of OE on NET formation was identified through SytoxGreen quantitative analysis and fluorescence staining. In addition, OE was used to treat collagen-induced arthritis (CIA) mice, and the incidence and severity of arthritis were assessed.
ResultsCompared to healthy controls, the levels of cfDNA in plasma and synovial fluid of RA patients were increased. The plasma levels of cfDNA were positively correlated with the ESR, CRP, RF IgM, RF IgG, DAS28-ESR and DAS28-CRP. Increased NET formation was also found in neutrohpils from RA patients. OE had no obvious cytotoxic effect on neutrophils and significantly decreased ROS production. Furthermore, OE significantly reduced the production of NETs in neutrophils from individuals with RA. OE effectively reduced the morbidity, arthritis severity, and NET deposition in the CIA mice.
ConclusionsIn this study, OE has been demonstrated a strong anti-arthritic effect in the context of RA. The potential mechanism by which OE ameliorates RA involves inhibiting ROS production by neutrophils, thereby reducing the release of NETs.